Maybe he was once a Nord, then got corrupted over time by Hermaeus Mora, so he became something more terrifying. Or maybe he's just like a normal Dragon Priest, or something completely different.

The little mermaid

The enticing allure of true power in the dragon tongue became too much for him. He purposefully gave it to the dragon cult as proof of his leaving for the devil of the ancient nordic pantheon, Herma-Mora, now known as Hermaeus Mora. Upon receiving the mask, the highest ranking of the dragon priests sealed the powerful artifact away in a pocket of time that required an elaborate series of keys, the likes of which could only be accessed and unlocked by the entire group of dragon priests. When the three nordic heroes eliminated Alduin and the dragon cult retreated into the pockets of Skyrim. The first dragonborn, after forging a second mask devoted to his new god, heard of the defeat of the dragons and the dragon cult and responded by sealing himself away in Hermaeus Mora's realm until their undoubted return that he knew was to culminate evenutally due to his master's prophetic knowledge. As for the secret of accessing this legendary mask, it was lost until an explorer found notes telling of it and its whereabouts with only a few pages regarding the path to access this alleged "temporal pocket". Cue you, the new Dragonborn. (purely speculation, don't take this for fact)

Is Mora Ursula, then?

Another interesting point is that would the dragon cult, who considered the dragons gods, have considered this first dragonborn a demigod?

Call her what you wish, but in the end she will always be Ariel to me.

They did until he betrayed them.

Oops misread. Snip

Argenir or however you spell his name, that'd make me laugh

The idea of that actually made me laugh! I'm just imagining his old face appearing from behind the mask Darth Vader style.

well his voice doesnt rumble like the other greybeards so maybe its some double soul aspect thing... that or his vader voicebox is locked in apocrypha

IT'S OLD MAN JENKINS!!! http://www.youtube.com/watch?v=QEDeVHinRps&feature=player_detailpage#t=3s

this is about seeing what's under his mask after you kill him...
but if you can use Dead Thrall, then yes, it can be your friend

He's clearly a human avatar of Cthulhu. Silly fools...

or perhaps he's the elusive were-squid, bane of whales and maker of bridges in the afterlife...

That's some mighty fine speculation!

That would be the most EPIC thing Bethesda has ever done. I seriously want. Seriously.

A Sload named Xarxes.

I'm really not sure... some kind of face I imagine.


Also this ^

Of course! I should have seen this from the very start. Might want to put some of them what the city folk call spoiler tags around that.

Darth Nihilus

Dovahbear

Jim Carey. http://www.youtube.com/watch?v=ttoC1n8z9h4

That would the greatest moment in gaming history!